(I) In the medical field, medical devices that include a part coming into contact with a living body, such as catheters, tubes, endoscopes and insertion tools, are required to have a lubricant surface for inhibiting damage to a living body and deterioration of an apparatus that are caused by friction due to contact and for improving the operability. However, conventional surfaces generally exhibit low lubricity upon coming into contact with a biological tissue or the like and have poor hydrophilicity; therefore, such conventional surfaces may cause problems such as deterioration of a medical device due to friction, inflammation of a living body, and the like.
In view of this, for improvement of the surface lubricity of a device, there have been proposed methods in which a functional group is generated on the surface of a device by performing an ozone treatment or a plasma treatment and a hydrophilic polymer is subsequently graft-polymerized on the device (Patent Documents 1 and 2). Further, a method of coating the surface of a medical equipment with a urethane resin having a hydrophilic moiety has been proposed (Patent Document 3).
(II) Adherent cells such as macrophages and fibroblasts are called “anchorage-dependent cells” since they are activated and proliferate only when they adhere to an adherend. Adhesion of these cells is induced via protein families (adherent molecules and proteins) found in the extracellular matrix, such as vitronectin and fibronectin. Such cell adhesion presents problems in various fields, including the medical field.
For example, fibroblasts added to a culture medium adhere to a tissue culture plate via extracellular matrix proteins. Similarly, in urinary catheters, bacterial cells adhere to the catheter wall and, for example, platelets adhere to the tip of an arterial catheter and, on contact lenses, such adhesion creates a state where cells cover the lens surface via proteins. The occurrence of such cell adhesion in a medical equipment, an apparatus or the like in this manner creates major problems since it not only simply causes contamination but also results in, for example, clogging and reduction in analysis accuracy and sensitivity.
In view of this, as a technology for inhibiting non-specific adhesion of a biological substance to a container, a copolymer of 2-methacryloyloxyethyl phosphorylcholine and a methacrylic acid ester has been described to make adhesion and aggregation of platelets as well as adhesion of plasma proteins unlikely to occur (Patent Document 4).
Further, as a protein adsorption inhibitor, for example, a copolymer of 2-methacryloyloxyethyl phosphorylcholine with n-butyl (meth)acrylate, methyl (meth)acrylate or styrene has been described (Patent Document 5).
For anchorage-dependent cells, basically, a monolayer culture method is mainly employed; however, the resulting cultured cells often have properties different from their in vivo properties. For example, in the industrial application of a protein or the like produced by such cells, it is known that, by three-dimensionally culturing the cells and thereby forming cell clusters, functions closer to those of the cells existing in a biological tissue can be exerted (Non-patent Document 1). Conventionally, as methods forming a cell cluster, for example, hanging-drop method, gyratory culture method, methyl cellulose method, and three-dimensional sphere method have been known.
(III) Microchannel devices have many advantages in that, for example, they are available in small quantities and many types and have high efficiency and low environmental load; therefore, in recent years, such microchannel devices have been utilized for the synthesis, analysis, extraction, separation and the like of substances. As the substrate materials of these devices, glasses and resins are known. Thereamong, silicone rubber substrates are useful since they can be easily micro-processed and have excellent optical transparency and chemical resistance.
The above-described devices usually have a 0.1 μm to 1 mm microchannel, and transfer, reaction or measurement of a liquid, microparticles, gel substance or the like is performed inside of this channel. Such devices enable to perform, for example, the measurement and detection of a biological sample, such as a blood sample, in a short period of time.
However, since the channels of such microchannel devices are narrow, there is a problem that adhesion of a biological sample or the like to the channel surface is likely to cause a reduction in flow rate. In addition, adhesion of a sample component to the channel surface makes the channel even narrower, and the effects of the loss of a reagent or the like on measured values are not negligible. Furthermore, since silicone rubber substrates have a low affinity for water, when a liquid including water is allowed to flow in the channel, poor fluidity potentially makes it impossible to accurately perform a desired operation. Therefore, it is necessary to hydrophilize the channel surface so as to inhibit the adhesion of a sample component thereto.
In view of this, for the purposes of improving the wettability of a microchannel with water, preventing a chemical liquid from remaining in a micropump and stabilizing the quantitative accuracy or detection accuracy, it has been proposed to form a layer of a sulfur compound having a hydrophilic group as a terminal group on a metal layer surface of a microchannel (Patent Document 6). Further, it has been also proposed to modify the inner wall surface of a microchannel with a fluororesin or the like (Patent Document 7), and to coat the surface with polyethylene glycol, Eval, Poval, or a polymer having a phosphorylcholine group (Patent Document 8).